RE: [Linux-cluster] fencing device

From: "Hofmeister, James (WTEC Linux)" <james hofmeister hp com>

To: linux clustering <linux-cluster redhat com>

Subject: RE: [Linux-cluster] fencing device

Date: Wed, 10 Dec 2008 08:48:20 +0000

Hello all,
|HP iLO is supported as a fencing device. If you are serious,
|you should still consider power fencing (don't forget, that
|fencing can be a SPOF, you need two fencing devices).
ILO is used on many sites successfully.
|iLO/IPMI fencing has some serious consequences:
|- It's not a shared device. It MUST be on the same network path as
| heartbeat.
Not true... I have my ILO on my public network and my heartbeat on a private network switch. No problems with fencing in this configuration.
|- Server out of power = iLO out of power. After a recent update of cman
| in RHEL5.2, rgmanager now waits for fencing to complete before
| starting any services. If one node is offline (away for repair, etc.)
| then it's fencing will never complete and you are stuck.
I have some ILO issues to be fixed in RHEL-5.3 for fencing on blades... The situation I have seen is you must be successful in power off and power on for the ILO fence to complete as you suggest. I hope this will would be changed and that a ILO power off would be sufficient. In the case of "away for a planned repair" you would not perform an ILO fence, rather you would shutdown the node in the cluster gui.
I hope this helps.
Regards,
James Hofmeister (HP Linux).